Earth boring mechanism and coordinated pilot hole drilling and coring mechanisms

ABSTRACT

A cylindrical member is lowerable through a drill pipe and latched thereto. Cutters carried on arms hinged to slots in the cylindrical member move outwardly under pressure of the drill fluid through gaps in the lower end of a shoe at the bottom of the drill pipe to underream under the shoe. The cylindrical member has a pilot bit at its lower end and a core barrel in its bore. Roller or diamond cutters may be used.

United States Patent [1113565192 References Cited UNITED STATES PATENTS2,277,989 3/1942 Kinnear.......,..............

l75/247X 175/258 l75/330X 175/246 175/330 9/1943 Sewell ,335 5/1945Walker......

3/1956 Williams.......

[72] Inventor Frank W. McLarty 337 S. Edgeeld Ave., Dallas, Tex. 75208[2l] Appl. No. 755,471 [22] Filed Aug. 27, 1968 [45] Patented Feb. 23,1971 [54] EARTH BORING MECHANISM AND COORDINATED PILOT HOLE DRILLING ANDCORING MECHANISMS 12 Claims, 55 Drawing Figs.

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1. An earth-boring mechanism employing in continued workable cooperativeconjunction in all kinds of rocks: a rotatable tubular cylindrical drillpipe having threaded means on the lower tip thereof whereby is fixedlyattached to said lower tip a tubular cylindrical shoe having through thelower margin thereof multiple gaps, equally spaced from each otheraround the rotational axis of said shoe and drill pipe with each gaphaving one vertical side thereof in said shoe margin; means attached tothe interior cylindrical wall of said shoe intermediate said gapstherein whereby there is rotationally oscillated within said shoe,around its rotational axis, a generally cylindrical central main bodymember, having an outside diameter very slightly less than internaldiameter of said drill pipe, and having a vertical cylindrical canalthrough the center thereof having adequate diameter to carry downwardunder pressure sufficient drilling fluid to carry all rock cuttingsupward around said shoe, of a rock drilling mechanism installablethrough said drill pipe and having means attached to the cylindricalexterior thereof that operate in conjunction with said means attached tothe interior cylindrical wall of said shoe, when said body member enterssaid shoe from said drill pipe, thereby so rotationally disposing saiddrilling mechanism with respect to the gaps in the lower margin of saidshoe, when the means attached to the interior wall of said shoeultimately limit downward movement of the drilling mechanism in saidshoe and thereby prevent passage completely through said shoe, that armshingeably mounted adjacent their upper tips in vertically disposed slotsin the exterior wall of said central body member and having rockdisintegrating means attached to the lower tips thereof are free tohinge outward into said respective gaps in the lower margin of saidshoe, which thereafter in rotational drilling limits outward hinging ofsaid arms and simultaneously rotates directly, around the rotationalaxis of the drill pipe, said arms, whose rock disintegrating meansattached to the lower tips of said arms respectively serve to underreamthe drillpipe shoe in the rotational drilling process.
 2. Anearth-boring mechanism specified in claim 1 in which the cylindricalmain central body member thereof, having an external diameter almost asthe tubular cylindrical drill pipe through which it is installed in thetubular cylindrical shoe, fixedly attached to the lower tip thereof andhaving means preventing said central body member from passing on out thelower end of said drill pipe, is provided with means in the upper partof that main central body member whereby hydraulic pressure of drillingfluid, descending through the drill pipe, (at the election of thedriller controlling connection of said drill pipe with a pump driven bysuitable means adjacent the head of the well, and into a suitablevertical canal passing through the center of the generally cylindricalmain body member, actuates the upper tips of multiple suitable dogspivotally mounted in respective vertical slots in the upper portion ofsaid main body member to force said upper tips of said dogs outward fromsaid main body member and into an annular space below the lower end ofthe drill pipe having its threaded lower tip screwed into the tubularcylindrical shoe fixedly attached thereto, thereby causing said mainbody member pivotally mounting said dogs in the slots therein to remainfixed with respect to the shoe and drill pipe in which it thus becomesfixedly mounted until such time as the hydraulic pressure of the pump atthe head of the well is cut off by the driller, at which time suitablesmall springs mounted in the respective slots in the main body membercause said dogs to recede into said slots to such extent that said mainbody member can be drawn upward through said drill pipe by means of asuitable cable having attached to Its lower tip a grappling mechanism ofsufficient weight that the grappling mechanism becomes attached to alifting device attached to the upper part of the main body member, whenthe said grappling mechanism and the lower tip of the cable to which itis attached descends sufficiently through the drill pipe from a suitablereel from which it unwinds at the head of the well.
 3. An earth-boringmechanism specified in claim 1 in which the central body member of thedrilling mechanism has a vertical cylindrical canal through the centerthereof, carrying drilling fluid downward and having a diameter at leastabout one-fifth as great as the diameter of the drill pipe, and hasmultiple vertically disposed slots, around said vertical canal, in theexterior wall of the generally cylindrical central body member, throughwhich slots, near the upper tips thereof, are mounted correspondinghorizontally disposed hinge pins at different elevations in the saidgenerally cylindrical main body member, on which hinge pins arehingeably mounted said arms that hinge outward toward their lower tipsinto the respective gaps in the lower margin of said drill pipe shoe,below which the rock-disintegrating means in the lower tips of said armsin the rotational drilling process underream a hole of sufficientdiameter for the drilling fluid to carry most effectively the rockcuttings upwardly around the drill pipe shoe and the multiple threadedcouplings by which the joints of the drill pipe are joined together. 4.An earth-boring mechanism specified in claim 1 in which the generallycylindrical central body member of the drilling mechanism has a centralvertical cylindrical canal, carrying drilling fluid downward through thecenter thereof and having a diameter at least about one-fifth as greatas the diameter of the drill pipe, and has in the exterior wall of thegenerally cylindrical central body member and disposed around saidvertical fluid carrying canal of said approximate diameter, multiplevertically disposed slots, in each of which is hingeably mounted on ahorizontal pivot pin a vertically disposed arm, which during thedrilling process, after the cylindrical main body member becomes fixedlymounted in the drill pipe shoe with respect to which it will not rotatethereafter, is hinged outwardly at its lower tip into one of theduplicate gaps in the drill pipe shoe by means of pressure of thedrilling fluid, descending through the central canal of the main bodymember at the election of the driller controlling a suitable pump at thehead of the well, exerted outwardly on the lower half of each said armby a short cylindrical prod rod mounted loosely in a small canaldisposed at an angle with respect to the horizon and connecting thecentral canal to the vertically disposed exterior slot in the outer wallof the main body member in which said arm is hingeably mounted.
 5. Anearth-boring mechanism specified in claim 1 in which the generallycylindrical main body member of the drilling mechanism has a verticalcylindrical central canal, carrying drilling fluid downward through thecenter thereof to the multiple rock-disintegrating means and having adiameter at least about one-fifth as great as the diameter of the drillpipe, and has in the exterior wall of the generally cylindrical centralbody member, and disposed around said vertical fluid-carrying canal ofat least the said dimension, multiple vertically disposed slots, in eachof which is hingeably mounted on a horizontal pivot pin a verticallydisposed arm, which during the drilling process, after becoming mountedin the drill pipe shoe, is hinged outward at its lower tip, mountingrock disintegrating means, into one of the duplicate gaps through thelower margin of the drill pipe shoe by means of the following mechanism:a pair of duplicating vertically disposed cylindrical holes, spacedapart from each other and from the vertical central canal, drilledupward in the central body member into the corners of the floors of theverTical slots in which the said arms are hingeably mounted; acylindrical push rod, having a conical upper tip, slidably mounted ineach of said holes beneath the diagonally disposed lower face of thelower tip of the arm mounting the rock disintegrating means so disposedthat upward pressure on the pair of duplicate pushrods will force theconical upper tips of said rods between the inner face of the verticalslot and the inner face of the arm mounted hingeably therein, which armthereby has its posture adjusted from vertical and has its lower tiphinged outwardly through the respective gap in the lower margin of thedrill pipe shoe; and means reciprocating said multiple arm-adjustingpush rods consisting of a tubular cylindrical integrally attacheddownward extension of the main central body member, of smaller outsidediameter than said main central body member, into which all of themultiple said vertical holes, accommodating the respective paired armadjusting pushrods, extend, but have their lower approximate halvesconverted into hemicylindrical slots by virtue of the increased diameterof the vertical canal in the lower half of said tubular cylindricaldownward extension of said central body member, onto whose externallythreaded lower tip is screwed a suitably threaded cup-collar thatslidably retains in said enlarged lower half of said downward tubularcylindrical extension of the central main body member a tubular aligningand connecting member having a midsection, of greater outside diameterthan the tips thereof, to which the lower tip of each of the multiplevertically disposed adjusting pushrods is attached fixedly, so thatreciprocation of said tubular cylindrical connecting member with respectto the main body portion of the drilling mechanism hingeably mountingthe several arms therein serves to adjust the angle of disposition ofsaid arms from the vertical positions to which they tend to be heldinside their respective slots inside the cylindrical tubular drill pipeby means of small resilient springs mounted around the respective hingepivot pins on which the respective arms are hingeably mounted; and meansof effecting such reciprocation for adjustment of the angles ofdisposition of said arms from vertical consisting of suitable tool-jointaccommodating threads mounted on the conical lower tip of the saidtubular cylindrical aligning and connecting member onto which isscrewed, below the above-mentioned internally threaded cup-collar, anadapter bushing having corresponding internal tool-joint threads wherebythere is attached fixedly to said tubular cylindrical aligning andconnecting member a drilling mechanism boring a pilot hole, downwardlyahead of the aforesaid underreaming mechanism, having a diameter almostas large as the internal diameter of the drill pipe through which thegenerally cylindrical central body member is made to descend, untilfurther downward travel is limited by the shoe mounted on the lower tipthereof.
 6. An earth-boring mechanism specified in claim 5 in which thedrilling mechanism boring the pilot hole ahead of the underreamingmechanism bores an annular groove around a rock formation core, whichthereafter is retained in an inner core barrel provided with a suitablecore-catching mechanism, whereby the rock core segment of the formationpenetrated is lifted to the well head by means of a cable attached tothe upper portion of the main generally cylindrical body member by agrappling member attached to the lower tip of the cable descendingthrough the drill pipe and provided with means whereby said grapplingmember of sufficient weight to draw the tip of the cable downward and toattach itself to means connected to the said main generally cylindricalbody member.
 7. An earth-boring mechanism specified in claim 1 andemploying the following: a generally cylindrical central main bodymember which has in its outer wall four vertically disposed slots, inwidth about one-third of the outside diameter of the drill pipe shoe, inthe upper inner tips of which are located vertically disposed ribs,about one-half as wide and one-half as long as said slots respectively,integrally attached to the central section of the body memberintermediate said slots, in each of which is hingeably mounted an arm,having industrial diamonds mounted on the lower tip thereof, on a pivotpin having its tips fixedly mounted in said body member, with itshorizontally disposed longitudinal axis parallel to the axis of one ofthe other pivot pins and at right angles to the other two, which haveparallel axes disposed at a level almost an inch higher than the axes ofthe first two pivot pins, and extending through the upper tip of saidarm, which tip in horizontal cross section is substantially U-shaped andextends around its respective body rib, which is almost square in crosssection at the axis of its hinge pivot extended therethrough, belowwhich the outer face of the respective rib gradually slopes inwardly, atan angle about 30* from vertical, toward the inner wall of therespective slot and disappears as a rib about halfway downward towardthe bottom of said slot, which is at the same level as the bottoms ofthe other three slots; a pair of resilient U-shaped springs mountedaround the hinge pivot pin of each of the respective arms tending tokeep inclosed in its respective slot each of the said arms, on the lowertip of each of which are suitably mounted industrial diamonds, whichtend in combination, by virtue of the fact that the lower tips of allsaid arms reach downward to the same substantial arcuate level in theirrespectively accommodating slots, while one diametrically opposed pairof the mounting pivot pins is mounted higher in the body member than theother two diametrically opposed pivot pins at right angles thereto, tounderream in the drilling process an enlarged hole of suitable diameter,in excess of the outside diameter of the drill pipe shoe, around a pilothole, having a diameter almost but not quite as great as the insidediameter of the drill pipe, drilled by suitable means below thegenerally cylindrical main body member in which the four arms arehingeably mounted; hydraulic means whereby the driller, at his election,can hinge all four of said diamond-mounting arms outwardly, into theirrespective gaps in the lower margin of the drill pipe shoe by the fullarc for each arm permitted by each of the respective duplicate gaps insaid shoe, by control of pressure in the drill pipe connected to thevertical cylindrical canal in the center of the generally cylindricalmain body member, in which said canal its diameter is reduced slightlyin the midsection thereof and below four small cylindrical canals,suitably disposed at angles with respect to the horizon and at rightangles to each other in pairs at slightly differing levels, leading fromthe upper segment of said central canal having the larger diameter tothe respective four slots through the central ribs in the upper innercorners of those slots, into which project the outer tips of fourcylindrical prod rods of suitable short length that fit loosely in theirrespective canals, in which pressure from the central vertical canal, atthe election of the driller, forces the outer tips of those prod rodsagainst the said diamond-mounting arms intermediate the tips thereof andthereby forces the outer wall of each of the four arms against the roofof its respective gap in the lower margin of the drill pipe shoe; andmeans keeping the underreaming mechanism, and the larger hole drilled inthe rock formations thereby, suitably aligned with the lower smallerpilot hole by employing the following: a tubular cylindrical downwardextension of the main body member, said downward extension having anoutside diameter only slightly less than the diameter of the cylindricalpilot hole, on whose lower tip are provided suitable threads wherebythere is attached to said tubular cylindrical downward extension aguiding tubular cylindrical member, of suitable lengtH and outsidediameter to slip easily through said lower pilot hole, whose lowerinternally threaded tip is closed by a slightly conical member having avertical hole through the center thereof, in which is fixedly mounted amuch smaller vertically disposed pipe having suitable means at the uppertip thereof connecting it to the lower tip of the aforesaid downwardtubular extension of the main body member, there being adjacent theupper tip of the guiding tubular cylindrical member multiple orificesthrough the wall thereof to permit larger rock cuttings to drop intothat retaining bucket member from the drilling fluid flowing upwardaround said tubular cylindrical guiding member.
 8. An earth boringmechanism employing in continued workable cooperative conjunction: aninternally threaded tubular cylindrical shoe screwed on the lower tip ofa rotatable vertically disposed string of tubular cylindrical drillpipe, through which is installed from the head of a well a drillingmechanism whose generally cylindrical main central body member, havingan outside diameter almost as great as the internal diameter of thedrill pipe through which it is easily slidable, is prevented by saidshoe from passing out of the lower tip of said drill string at any time;a tubular cylindrical linkage member fixedly attached by suitableinternal threads to the upper threaded tip of said main body member,having a vertical canal through the center thereof with a diameternearly one-third that of the cylindrical drill pipe, and to the lowertip of a threaded and aligned second tubular retainer member, of smallerdiameter than the first and of suitable short length of several inches,whose upper externally-threaded tip is screwed into the lower tip of alifting and aligning tubular cylindrical member several feet in lengthhaving a suitable upper tip, whose outside diameter is almost as greatas the internal diameter of the drill pipe through which it is easilyslidable, and whose upper face slops downward conically toward therotational axis of the drill pipe and of the main body member of thedrilling assembly installable and removable through said drill pipe; ahorizontally disposed circular lifting plate, having a suitable roundhole in the center thereof, fixedly attached to said lifting andaligning tubular cylindrical member, immediately above the upper end ofthe short tubular retainer member, whose upper tip is screwed into thelower tip of said lifting and aligning tubular member, provided with asuitable spider framework attached fixedly to the cylindrical wall ofsaid retainer member and mounting fixedly in the center thereof a smallvertically disposed tubular cylindrical seating member, through whoseinternal threads is screwed a threaded cylindrical adjusting rod havingan upper tip with a conical upper face, whose level of disposition insaid retainer member is secured by a pair of nuts screwed on thethreaded cylindrical adjusting rod immediately above and below thetubular seating member; and a suitable grappling means attached to thelower tip of a cable inserted through the drill pipe when desired andemploying the following: four vertically disposed lifting members ofsufficient length to provide sufficient weight to pull downward rapidlythrough said drill pipe filled with drilling fluid the lower tip of theretrieving cable, around which all the four said substantially straightlifting members are fixedly attached thereto by means separating saidlifting members from each other and disposing them with their lower tipstending to remain separated from each other by at least the samedistances as at the lower tip of the lifting cable, there being attachedto the lower tip of each such substantially straight lifting members,having lower ends that slope upwardly toward the axis of the verticallydisposed cable, multiple angular latching devices whose upper facesslope upwardly toward their outer tips, which during downward travel ofthe cable tip are drawn together by a strong cord wrapped and tiedtightly around the four vertically disposed lifting members immediatelyabove said latching devices, whose combined horizontal extent is thusminimized to such degree that said latching devices pass readilydownward through the suitably shaped round hole in the center of saidhorizontal lifting plate, whose lower face slopes upwardly from saidcenter hole so that the latching devices will not return upward throughsaid center hole in said lifting plate, in response to subsequentlifting of the cable, after the aforesaid strong cord is broken bydownward falling of the four said lifting members against theaforementioned conical upper face of the spearlike cylindrical adjustingrod, mounted fixedly in the center of the tubular cylindrical retainermember a suitable distance below said horizontal lifting plate, whichspreads apart the lower tips of the four substantially straight liftingmembers to which respectively the latching devices are rigidly attached,thereby affording a suitable linkage between the lower tip of said cableand the generally cylindrical main body member of the drilling device.9. An earth-boring mechanism employing in continued workable cooperativeconjunction: an internally threaded tubular cylindrical shoe screwedonto the lower tip of a rotatable vertically disposed string of tubularcylindrical drill pipe, through which is installed from the head of thewell a drilling mechanism whose generally cylindrical central main bodymember, having an outside diameter almost as great as the internaldiameter of the drill pipe through which it is easily slidable, isprevented by said shoe from passing out of the lower tip of said drillpipe string; a tubular cylindrical aligning retainer member at leastnearly one foot long and having the same outside diameter as thegenerally cylindrical main body member, to which it is fixedly attachedby threads in the lower tip thereof screwed onto the external threads ofan upper reduced diameter segment of said main central body member,above the upper end of which by a fraction of an inch are the lowerfaces of at least two diametrically disposed generally rectangularopenings openings, about 1 inch wide and nearly 2 inches high, throughthe wall of said aligning retainer member, through which openings insaid wall respectively are extendable the upper tips of suitablediametrically opposed scotching dogs, whose upper tips during thedrilling process are projected into the annular space inside the drillpipe shoe immediately below the lower end of the drill pipe, and whoselower cylindrical tips are mounted in cylindrical cups in the upper faceof the main central body member, to which each of said scotching dogs ispivotally attached at its lower tip by means of an arcuate plate havinga notch in one side for accommodation of the pivotally mountedoscillatable scotching dog, whose hinge pivot pin is held to the upperhorizontal face of the main central body member by bolts extendingthrough holes in said arcuate plate, so that it is possible to pivotallyattach the respective dogs to the central body member of the drillmechanism, after there has been mounted on said central body member thetubular cylindrical retainer member and suitable means of adjusting tiltof the said scotching dogs in unison; means of retracting the upper tipsof the scotching dogs in unison from their positions in the annularspace in the drill pipe shoe, beneath the lower end of the drill pipe,consisting of a tubular cylindrical adjusting member vertically slidablein an annular cavity in the upper tip of the main central body memberand within the tubular cylindrical retainer guiding member, saidadjusting member having suitable rectangular notches in its upper marginto accommodate the respective scotching dogs, each of which restssubstantially on the lower face of its respective notch in saidcylindrical adjusting member, when the upper tip of the scotching dog isextended outwardly througH the hole in the wall of the tubularcylindrical retainer member, which has attached to its inner uppermargin multiple vertical adjusting rods, intermediate the respectivenotches in said tubular cylindrical adjusting member, whereby thetubular cylindrical adjusting member is fixedly attached by the uppertips of said vertical adjusting rods of suitable equal short length to ahorizontally disposed circular lifting plate, slidably mounted insidethe said tubular cylindrical guiding retainer member, provided with asuitable hole in the center thereof, whereby a suitable grapplingmechanism fixedly attached to the lower tip of a cable extendingdownward, when desired, from a suitable reel at the head of the well isemployed to raise the horizontal lifting plate, the multiple verticallydisposed adjusting rods fixedly attached thereto, and the tubularcylindrical adjusting member fixedly attached to the lower tips of saidadjusting rods, thereby slightly raising in unison all the outer tips ofsaid pivotally mounted scotching dogs and thus retracting them inwardly,from the annular space in the shoe beneath the lower end of the drillpipe, toward the rotational axis of the drill pipe, so that the uppertips of said hingeably mounted scotching dogs become retracted intotheir respective holes through the wall of the tubular cylindricalguiding retainer member, which in turn lifts the main central bodymember rigidly attached to its lower tip, when the horizontal liftingplate rises a fraction of an inch and thereby comes in contact with themovement limiting lower face of an annular cylindrical member, having anoutside diameter the same as the outside diameter of the guidingretainer member, easily slidable in the drill pipe, having externalthreads, formed on a lower segment of reduced diameter, screwed into theupper guiding retainer member, whereby directly the entire drillingmechanism is lifted through the drill pipe, when the suitable grapplingmechanism on the end of said cable descends through the downward slopingconical upper face of said annular cylindrical member provided with acylindrical hole at the center thereof very slightly larger in diameterthan the hole in the center of the horizontal lifting plate; a diffusingspear member having a conical upper face fixedly disposed in the centerof said tubular cylindrical guiding retainer member, a suitable distancebelow the hole in the center of the horizontally disposed circular plateattached to the upper tips of the four adjusting rods, whereby multiplelatching members attached to the lower tips of vertical members of thegrappling device attached to the lower tip of a cable extendingdownward, at the election of the driller, through the drill pipe arebrought into contact with the lower face of the horizontal lifting platearound the hole through the center thereof, when the cable is raisedupward to effect such lifting of the drilling mechanism through thedrill pipe for any reason; and means tending to keep the upper tips ofthe hingeably mounted scotching dogs caught beneath the lower end of thedrill pipe in the drill pipe shoe, until such time as the cable liftsthe tubular cylindrical adjusting member through whose notches thosescotching dogs are disposed, said means of keeping the upper tips of thescotching dogs outwardly extended employing the following: a shorttubular cylindrical sleeve, fixedly attached to the wall of the tubularcylindrical guiding retainer member in the midsection thereof, beneathwhich is mounted the upper tip of a resilient coiled compression spring,whose lower tip rests on the upper end of a short tubular cylindricalsleeve, having an outside diameter slightly less than the tubularcylindrical guiding retainer member, in which it is easily slidable,whose lower end, suitably rounded in cross section for easyaccommodation of the several scotching dogs, rests on the diagonallydisposed upper faces of the multiple hingeably mounted scotching dogs,whose upper tips thus tend to be Forced outward as far as possible bythe downward force of the resiliently flexible coiled compression springacting on all said scotching dogs in unison.
 10. A rotary coringmechanism employing in continued workable cooperative conjunction thefollowing: a tubular cylindrical outer core barrel serving as arotatable drill pipe whose lower tip core barrel fixedly attached bysuitable threads to the upper tip of an annular drill head member,having an outside diameter the same as said rotatable drill pipe, whoseupper conical face slopes downward to a cylindrical hole, in the centerthereof and about an inch deep, internally threaded for receiving asecond rotatable core barrel, whose inner diameter is the same as thatof the smaller cylindrical hole extending almost all the way throughsaid annular drill head member with that diameter and thereafter all theway through with a slightly smaller diameter, there being a narrowcircular horizontal shoulder adjacent the lower tip of said annulardrill bit member, somewhat longer than its horizontal outside diameter,on which shoulder rests a nonrotating core-catching device, of the sameinternal diameter as the lower smallest cylindrical hole through thelower tip of said annular drill head member, on which in turn rests anotched nonrotating inner core barrel having the same internal diameteras the nonrotating core-catching member and the hole through the lowertip of the aforesaid annular drill head member, which has an outsidediameter more than halfway upward from its lower end that is onlyslightly more than three-fifths of the diameter of the tubularcylindrical drill pipe attached to its upper threaded tip; a diagonallydisposed face, conveniently 30* from vertical, cut across said annulardrill head member and extending upward diagonally outward from the lowerend of the smallest hole through the center of said annular drill headmember, into which a hole of suitable diameter is drilledperpendicularly, at a suitable distance upward from said lower tip, andinternally threaded for receiving a tip-threaded stud bolt secured insaid annular drill head member and serving to mount therearound theinner race of a suitable antifriction bearing, whose outer race ismounted in a suitable rolling cutter, made of suitable hardened steelalloy, whose rolling lower teeth disintegrate the surface of the rockformation immediately around a cylindrical core of small enough diameterto slidably enter the smallest diameter cylindrical hole in the lowertip of said annular drill head member; a second annular drilling headmember having an outside diameter at its upper end equal to the outsidediameter of the outer core barrel drill pipe and to the maximum diameterof the upper section of the first said annular drill head member, aroundthe lower generally cylindrical section of which is fixedly mounted thesecond said annular drill head section, which has a generally conicalupper face, corresponding to a conical lower face of the upper section,sloping downward toward the rotational axis of the two sections as anauxiliary means keeping the two sections aligned under verticalpressure, and which has multiple keys imbedded in said conical surfaceserving as very strong means, in addition to multiple bolts insertedperpendicular to the contact surfaces of the two annular drill headmembers, keeping the upper section from rotating with respect to thelower section, whose lower approximate three-fifths has integrallyformed on its outer cylindrical surface four vertically disposed outwardextensions by a small fraction of an inch, respectively having arcuateouter faces disposed at 90* intervals around the said second annulardrill head member; a suitable recession formed in the lower tip of saidsecond lower outer drill head section to accommodate loosely theaforesaid rolling cutter mounted on an axle pin fixedly attached bysuitable means to the lower tip of the smaller diameter lower section ofthe upper annular drill heAd member; a second axle pin having itslongitudinal axis substantially in the same vertical plane containingthe first said rolling-cutter axle pin fixedly attached to the lower tipof the upper said annular drill head member, but with the second saidaxle pin, suitably mounting rotationally a second suitable rollingcutter, being mounted in the lower tip of the lower and outer secondsaid annular drill head member almost member, almost through which, atthe midpoint plane of one of the outward arcuate extensions thereof, thethreaded hole mounting the threaded tip of said second axle pin extends,the axis of said second rolling-cutter axle pin, mounting a suitableantifriction bearing thereon, being disposed at a smaller angle than thefirst said rolling-cutter axle pin with respect to the horizon, and therolling cutter, provided with suitable teeth on a slightly conical faceof smaller maximum diameter than the diameter of the first said rollingcutter having a substantially cylindrical outer face for the teeththereof, describing an annular almost horizontal cutting path on thebottom of the hole larger than the annular rotational path of the firstsaid cutter by virtue of the suitable cylindrical cavity milled in thelower outer second said annular drill head member for rotationalaccommodation of the second said rolling cutter, for the rotationalaccommodation of which a suitable cavity also is cut in the adjacentouter wall of the telescoped lower segment of the inner upper first saidannular drill head member; a pair of diametrically disposed axle pins,mounted in a vertical plane passing through the rotational axis of thetwo telescoping annular drill head members perpendicular to the verticalplane including the axes of the two previously mentioned rolling-cutteraxle pins, mounted at suitable equal angles with respect to the horizonin suitable cylindrical cavities milled in the lower inner tip of theouter lower said annular drill head member, there being correspondingcavities milled in the outer wall of the inner said telescoped secondsaid annular drill head member rotationally accommodating the upperfaces of the two rolling cutters mounted on said pair of axle pinsprovided with suitable antifriction bearings for said substantiallyduplicate rolling cutters having suitable teeth in conical faces, whichdescribe an annular path disintegrating the rock formation and therebycutting a hole of slightly greater diameter than the diameter of thelower outer annular drill head member through the respective outwardvertical extensions thereof, between which the rock cuttings are carriedupward by the circulating drill fluid, for the downward passage of whichthrough the pair of annular drill head members multiple suitable smallholes are provided therethrough at least almost vertically.
 11. A pilothole drilling and coring mechanism consisting of a novel modifiedannular female ''''box'''' segment of a tool-joint screwed onto thelower ''''pin'''' segment of a conventional ''''internal upset''''flashwelded joint of drill pipe with said annular ''''box'''' beingmodified to achieve the following construction: (1) to a distance of 1inches below the lower end of the above-mentioned ''''pin'''' segment ofsaid conventional joint of drill pipe above it, said ''''box'''' isbored out internally to form a cylindrical canal of suitable diameter,below which said vertical canal becomes conical, at an angle of 30* fromvertical, until it reaches the original conventional cylindrical canalthrough said ''''box'''' segment of the tool-joint; (2) at a levelone-quarter inch below said conical section of the canal, an annularshoulder is created by boring that conventional cylindrical canal outdownwardly to an internal diameter one-eighth inch greater than abovesaid shoulder, thereby forming a cylindrical cavity in which in due timeis installed from beneath and fixedly therein a generally cylindricalinsert about 1 1/4 inches high having 12 vertical grooves aboutthree-sixteenth inch deep cut vertically out of the internal surface,remaining after the upper inner tip of said insert is bored outconically to continue the conical downward slope of the canal above saidinsert in said annular ''''box,'''' of said insert, on which internalarcuate surface between said vertical grooves are mounted multipleindustrial diamonds, by a sintering process well-known to the art, forreaming around a rock core remaining after the annular groove in therock formation has been cut around said cylindrical core by rotation ofsaid ''''box''''; (3) 12 vertical grooves provided in the inner wall ofsaid ''''box'''' and extending outwardly with their respective outerwalls being downward extensions of the outer wall of the vertical canalhaving maximum diameter in said annular ''''box'''' member, each of said12 grooves being disposed radially in said box with respect to thecorresponding 12 grooves in the inner cylindrical wall of the generallycylindrical insert, which is provided with very slight ribs inserted inthe respective said grooves in the surrounding ''''box'''' member tokeep said ''''box'''' from rotating with respect to the generallycylindrical insert, which also forms a small vertical canal, throughwhich drilling fluid is transmitted downward under pressure from thecanal in the drill pipe, in conjunction with each of the grooves in saidannular ''''box'''' member, in which those vertical canals extenddownward to the lower annular tip thereof, which is formed with ahemispherical vertical cross section; (4) 12 grooves formed in saidannular lower tip of said annular ''''box'''' member fixedlyaccommodating 12 J-shaped steel segments fixedly attached thereto bymultiple bolts and other means permitting easy removal therefrom toconveniently replace any of the multiple industrial diamonds installedon the drilling face of each of said 12 J-shaped steel mounting segmentsindividually without having to install diamonds in all of the drill bit.12. A pilot hole drilling and coring mechanism specified in claim 11 inwhich is installed from above through said conventional internal-upsetflashwelded joint of drill pipe an inner nonrotating tubular cylindricalcore barrel having fixedly, but removably, attached to the lower tipthereof a tubular cylindrical core-catching device, having an outsidediameter easily slidable through said conventional joint of drill pipeand having a lower tip that fits the upper inner face of the generallycylindrical insert around the rock core, which travels upward relativelywith respect to said nonrotating core barrel and into its telescopedsmaller vertically slit inner segment, in which said core is retained bya lower suitable collet provided with a suitable conical seat in saidtubular cylindrical member fixedly attached to the lower tip of theouter said nonrotating core barrel.